Magnetic moment of compass needle?

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Discussion Overview

The discussion revolves around the magnetic moment of a compass needle, exploring its typical value in SI units and the relationship between magnetic and electric dipole moments. Participants engage in theoretical modeling and practical considerations related to magnetism.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant inquires about a typical value for the magnetic moment of a compass needle in SI units.
  • Another suggests modeling the compass needle as a current loop and using the Biot-Savart law to determine the necessary current to produce a magnetic field, proposing a method to find the magnetic field through experimental means.
  • A third participant points out the lack of a typical value in the discussion and references external resources for calculating magnetic moments.
  • A participant expresses confusion regarding the units of magnetic moment compared to magnetic field strength, indicating a need for further reading on magnetism.
  • One participant is interested in comparing the magnetic dipole moment of the compass needle with its induced electric dipole moment in a strong electric field to assess potential deviations caused by the electric field.

Areas of Agreement / Disagreement

Participants do not reach a consensus on a typical value for the magnetic moment, and there are multiple competing views regarding the relationship between magnetic and electric dipole moments.

Contextual Notes

There are unresolved aspects regarding the definitions and units of magnetic moment and magnetic field strength, as well as the assumptions underlying the proposed modeling approaches.

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What would be a typical value of the magnetic moment of a compass needle (in SI units)?

Thanks :-)
 
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Do you know the B field of the needle? If you do try to model the needle as a little current loop, Use the biot savart law to find what current your loop needs to produce that B field. Your loop will have a diameter equal to the length of the needle.
Then just multiply the current times area
M=I(area)
Maybe you could find the B field of the needle by dropping it through a coiled copper wire and relating the change in flux to the voltage .
 
Thanks both, but I'm a little confused about the units. The strength of a magnet is given in Tesla, but that isn't the same as magnetic moment, is it? Obviously I need to read up on magnetism.

The reason I'm wondering is that I'd like to compare the magentic dipole moment of a compass needle with the induced electric dipole moment it might get in a strong electric field, to see if an electric field could possible cause any deviation of the needle.
 

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